Efforts have been underway since the early 1980's to develop effective chemotherapy for the treatment of HIV. BW935U83 is a reverse transcriptase inhibitor. This protocol was a phase I trial to evaluate the safety and pharmacokinetics of BW935U83 after multiple dosing in patients with HIV infection. BW935U83 was evaluated in 60 subjects in this dose escalation study. The drug was well tolerated by study subjects and pharmacokinetic analyses demonstrated excellent bioavailability with a plasma half life of 1.5 hours. The initial study investigated doses through 500mg po tid, but plasma HIV RNA levels and CD4 cell counts did not change on this dosage. Given the lack of drug-related toxicities, two additional dosage levels were added, (highest dose 1.3 grams po tid). Despite the documentation of plasma levels much higher than the IC50, no antiretroviral or immunologic effects were noted. Parallel studies which included BW935U83 in combination with AZT and 3TC failed to reveal any additional activity of the triple combination. Therefore the development of BW935U83 as an antiretroviral agent has been discontinued.